HUMANS are still made on the genetic framework of their hunter-gatherer forebears, and as such we not only have little need to eat grains, but by consuming grain may be damaging our health.

That's the provocative claim of American author Nora Gedgaudas, soon to visit Australia, whose 2009 book "Primal Body, Primal Mind" argues that our evolution designed us to consume fat, but very little sugar.

Sugar, in Ms Gedgaudas's interpretation, not only means the obviously sweet stuff.

It also includes non-fibre carbohydrates, including refined cereal products like bread and pasta, rice, and starchy vegetables like potato, all of which Ms Gedgaudas says are metabolised in the body as sugars.

"Two slices of bread, or a single small bagel, contain about six teaspoons of glucose," she wrote in "Primal Body, Primal Mind".

The body attempts to maintain blood glucose levels at the equivalent of around one teaspoon of glucose.

These states are a precursor to the modern epidemics of diabetes and obesity, and other chronic diseases, and may also impact on brain functioning - hence the "primal mind" of the book's title.

Wrote Ms Gedgaudas: "...high carbohydrate consumption, sugary, starchy and/or refined - and the vast tidal waves of insulin generated as a result - are a strictly modern phenomenon our primitive physiologies are ill-suited for."

"I'd say that there is no-one walking the Earth with a grain deficiency," she told Rural Press. "We can do beautifully - I'd say better - on a diet with no grains in it."

As a human fuel, Ms Gedgaudas likens carbohydrate to newspaper and kindling: it burns fast and strongly, but burns out quickly.

Ms Gedgaudas argues that we should be mostly running on "good" (Omega-3 rich) fats, a fuel that burns slow and long and doesn't need the constant top-ups of carbohydrates.

Low-carbs paying off for farmer

Walcha farmer Rob Blomfield removed refined carboydrates from his diet after reading Nora Gedgaudas's book while on holiday, and says he uncovered a man he hadn't known for years.

At 62, Mr Blomfield reckoned he felt like an 80-year-old. Now, he says, he's more like 40.

By the end of the first week off refined carbs, he'd lost the stiffness and soreness that had plagued him for a decade, and which he'd thought was the natural toll of being a farmer.

He shed a kilo a week for the first six weeks - "no gym, no different exercise," he comments - and now, seven months later, he's lost 14 kilos and kept them off.

Mr Blomfield used to take indigestion pills after each meal. He hasn't taken one since starting down the no-carbs route. And he lost the cramps that afflicted him at night.

"I didn't realise how hopeless I was until I started eating like this," he said.

The effect on his life of a relatively simple measure has impressed Mr Blomfield so much that he has overcome the usual farmer's reticence on personal matters to talk about it.

He's going to do so as a guest speaker at the Armidale seminar hosting Nora Gedgaudas, with whom he has no affliation other than as an admirer.

Meanwhile, he's off to play cricket for Walcha, for the first time in years, because for the first time in years he feels like he wants to.

Ms Gedgaudas is a National Association of Nutrition Professionals-certified nutritionist and neurofeedback specialist.

Her book had its origins in the wilderness of northern Canada, where in 1999 she was accompanying a biologist friend studying wolves. She was then eating a heavily vegetable-orientated diet and wary of fat, but on their infrequent returns to settlement found herself obsessed with butter.

At the same time she was wondering about the diets of the ancient Inuit, the remains of whose settlements are scattered through the region.

This speculation sparked an investigation into the evolutionary origins of diet and the discovery of the science around the so-called "paleolithic diet", an estimate of human diets before agriculture was born during the last 10,000 years of climatic stability.

There are now many different takes on the optimal "paleo diet", but all minimise the grain-based carboydrates that now dominate our eating, and emphasise meat and fats from grass-fed animals or wild-caught fish.

Ms Gedgaudas believes that if the source of protein is good - she advocates grass-fed meat, for instance - then the actual amounts consumed per day need only be modest.

On the other hand, she suggests that our need for vegetables has never been stronger, to help maintain bodily function under the assault of new compounds and stresses we are exposed to in modern life.

Ms Gedgaudas is a key speaker at the Nourishing Australia 2011 Seminar Series in Sydney, Armidale and the Gold Coast next month.

She will be joined by Costa Georgiadis from SBS Garden Odyssey, Bruce Ward of Holistic Results on grass-based livestock productivity, and David Mason-Jones, author of "Should Meat Be On The Menu", which argues that red meat production does not contribute to heightened greenhouse gas levels.